For finding the format of date and time with different form,then we can use the following code:
#include<Windows.h>
#include<stdio.h>
void main()
{
SYSTEMTIME var_t;
GetSystemTime(&var_t);
printf("%d\t:%d\t:%d\t:%d\t:%d\t:% d\t" ,var_t.wYear,var_t.wMonth,var_t.wDay
,var_t.wHour,var_t.wMinute,var_t.wSecond);
}

How far have you got and where are you stuck? This is *really easy* to do. This is not a free homework service; you must show your work and we will help you get unstuck. But I'm surprised you could be stuck with this; it's just a case of rearranging the string, so have you even tried?